rockwoodrv9

rockwoodrv9

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I posted a thread on how Boeing has restricted their 747 and Dreamliners from within 50 miles of any thunderstorms with the chance of icing and it was deleted for unknown reasons.

The reason for the post was that Boeing found ice where they didn't think could form. To me, that is something to look at very carefully. I have been a passenger in a light twin that turned into a popsicle between Aspen and Crested Butte. I believe this is an issue that deserves discussion and not be deleted by someone with an agenda. There are many places on an RV that ice would be a very bad thing.

I would like to know if anyone has tried the new products that put a coating on that repels water so well, ice won't form. I know there wes discussion several months ago but I haven't seen reports of how effective it was.

I am also interested in carb ice and peoples thoughts on carb vs FI. Being in a very cold area, maybe I should change to FI before I even start flying my plane. Is the typical set up for carb ice ok in Colorado? Maybe since it i so dry out here, there isn't as big of a problem as I believe?

If you want to see the article on the ice restrictions on the 747, I guess you will have to look that up.

Thanks for the info.
 
You can still get throttle body icing even with FI. I have experienced this a few times in Aztecs and my rocket.

A GOOD heat muff and carb heat set up works fine with a carb on an 0-320

The key is a heat muff that sufficiently heats the intake air as much or more than required. I have more comfort in intake icing conditions in my 0-320 AC than I do with the rocket.

As far as airframe icing goes the best option is to just avoid it period. I too am curious to learn more about the previously mentioned products that reduce or prevent the adhesion of ice. However, as Doug Rozendal once posted, rules 1,3,5,7 and 9 are NEVER fly in freezing rain.
 
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F1R said:
You can still get throttle body icing even with FI. I have experienced this a few times in Aztecs and my rocket.

A GOOD heat muff and carb heat set up works fine with a carb on an 0-320

The key is a heat muff that sufficiently heats the intake air as much or more than required.
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Thanks. That is info I can use. I hadn't considered getting ice on the throttle body. I am more than willing to give up performance to keep the engine warm enough. I have figured on putting shutters over the oil cooler and maybe even a blast tube to the throttle body area.

The winter is long and cold here and I don't want to limit flying to more than already is. Thanks again.
 
Rocky,

We loose several planes to induction icing every year in Colorado, frequently on blue sky Spring days. I don't know what ratio of carb versus FI engines.

Jim Berry
RV-10
 
Jim, that is what freaks me out - can be blue skys and still ice up. Didnt we learn that in the class we took together? I still refer to that weather book you gave me!

Your 10 is FI, isn't it? What do you think about carb - FI?
 
The Icing involved with the newer 747's is somewhat specific to jet engines. Its not a 747 problem but rather a engine problem. Its also a factor on other jet aircraft and has caused some changes to operating manuals. I was not aware of a restriction that required you to be 50 miles from a T storm as that would preclude flying at all in many areas of the world. The icing in question forms internally in the engine and is not airframe ice. It is caused by the engine taking in super cooled ice crystals. Normally this is not a issue for airframes because they do not stick at those temps.

George
 
George, I read the article and even posted a link to it but that post was deleted for some reason. I understand that was for the jet engines and specifically the 747, 87, and Dreamliner. They were taken out of service by JAL on several routes.

The part about the article that concerned me was it was icing in a location they didn't believe was a problem, but several events changed that.

I thought if I changed to FI from a carb, I would be ok. I now know that is incorrect and that the throttle body can freeze up.

Airframe ice is easy to see - at least in greenhouse planes like RV's. The carb ice or induction ice is what sneaks up on you.

I am still interested in how well the new coatings work to keep water off of aluminum. I worry about the areas on the wings, flaps, rudder, HS, that need to be clear of ice so they don't bind up. If the new coatings can help, that would be great. Even if it just worked for frost on the wings, it would save costly de-icing at the airport.

Look up the article - it is very interesting.
 
rockwoodrv9 said:
Jim, that is what freaks me out - can be blue skys and still ice up. Didnt we learn that in the class we took together? I still refer to that weather book you gave me!

Your 10 is FI, isn't it? What do you think about carb - FI?
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Rocky,

Yes, my -10 has AFP fuel injection. Love it! Both carb & FI can ice up, but my understanding has always been that it is much less likely with FI. I am sure someone will correct me if that is wrong. Fifteen -20 years ago, we had a series of forced landings in Colorado due to engine failure. Several of the pilots said they never thought about carb heat, because they didn't think they could have icing on a sunny, clear day.

If someone can give me the name of the super slippery stuff, I will try it on my truck this winter, and report the results. My recollection is that it has a milky appearance, so I am less excited about putting it on my plane

Jim Berry
RV-10
 
Icing is usually much worse in a carb than a fuel injection controller. Both have venturi's, which produce a small temperature drop. But most of the temperature drop is due to evaporating fuel (especially when it hits a throttle plate), which is present only in a carb.

Yes, you can get carb ice on a clear day. Just has to be enough humidity that it condenses out at some temperature below freezing (and then your carb has to be that cold).
 
Jim, with your beautiful paint job, I don't blame you for not wanting it on your plane! I think they sell one of the coatings at HD. Sold by Rustolium and called something like ever wet? I saw some and didn't realize what it was until I got home and looked at it.

Im going to be home from Dec 10 or so through Jan if you want to fly on over to Glenwood, Eagle, Rifle, or Aspen.
 
The icing referred to by Boeing most recently, concerns the 787 & the 747-8, and have the GENX engines (modern version of the CF-6). This type of icing involves ice crystal icing found at high altitude - generally 35K and up. Ice crystals are frozen and generally not a concern for airframe icing. However, when ice crystals are encountered near a thunderstorm, the water content (frozen) can be much higher. These ice crystals enter the engine fan section, can melt and then re-freeze either on the back side of the fan blades (low pressure, evaporative cooling), or possibly in a similar manner further back in the engine. Ice can build up in this manner and then possibly liberate when the blade flexes because of vibration caused by blade imbalance. Liberated ice can be ingested into the core, which can cause power interruption. The FADEC is very good at controlling the engine and restarting it if necessary. Boeing has recently recommended flight crews avoid flying over thunderstorms by 50 miles in certain GENX powered aircraft, in an attempt at avoiding ice crystal icing. The most susceptible area is above and slightly ahead of a mature thunderstorm. Descending through this area, while relatively benign looking on radar, can be loaded with ice crystals. They don't typically paint clearly on radar. Ice crystal icing was encountered by the Air France Airbus A330 a couple years ago off the coast of S. America. In this case, the engines worked perfectly all the way to the ocean (CF-6). Ice crystals melted and then re-froze in the pitot/static system, rendering it useless, and gave erroneous information to the flight crew and the flight management system.

This type of icing has nothing to do with what we do our RVs. As stated earlier, induction icing can happen in relatively humid air at varying temperatures and can affect injected engines, but is more likely in a carbureted engine because evaporative cooling in the throat of the carb. In most cases this can be managed.
 
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Scott, your explanation was much better than the article I read. Thanks. I know that particular type of iceing issue wasn't what we have to worry about, but the fact that it was out of the normal expectations for ice forming.

I guess there have been so many RV's flying in all kinds of weather that most possibilities have already happened. The thread not long ago about a jammed elevator and then pictures of lose bolts that could easily jammed a control serface made me thing about ice forming where it could not allow full movement. I haven't heard of that happening, but stranger things have happened.

Thanks for the info.
 
I haven't heard of icing so bad in an RV that it jams control surfaces, but that doesn't mean it hasn't happened, or that humans have discovered every way there is to screw up when it comes to dealing with cold weather and ice. I've heard of and experienced flow back icing, where a heated wing leading edge melted the ice and then it flowed back and re-froze on the wing in an unprotected area. That obviously can't happen in an RV, but freezing rain can and does freeze all over the airplane - even in flight. That could possibly cause the flight controls to behave poorly. It would not be unusual to experience freezing rain in VMC conditions (temperature inversion). I think if I encountered that, I would be making a quick 180, or looking for an airport ASAP. It's also possible to get slush or just water on and in your control surfaces and working parts that freeze hard after take-off. A good preflight that includes removing frozen and 'about to be frozen' contaminants from flying surfaces should be routine in the winter. Thank God for hangars!
 
Rocky,

My carbureted O320 has picked up ice a few times (nice humid mornings where I live). With the current engine monitor showing RPM, fuel flow, OAT, CHT, EGT, etc. it's been easy to suspect icing and add carb heat. Most of the time it was not icing but a few times it has been.

I do not worry about the possibility of icing because there are warning signs. I just use carb-heat as yet another control for engine operation.
 
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